With constant development of a network access technology and improvement of the capability of a terminal, multimedia (for example, audio and video) content is distributed to a plurality of terminals (such as a television set, a computer and a mobile phone). The multimedia content is generally borne and distributed by using an Internet Protocol (IP) technology. However, due to reasons such as network congestion, line noise, and a device fault, a case of network packet loss is unavoidable. In order to ensure reliable transmission of the multimedia content, a transmission protocol, such as the Transmission Control Protocol (TCP) or the Stream Control Transmission Protocol (SCTP), with a packet loss repairing function at a transport layer of a TCP/IP protocol stack, is generally adopted to bear the multimedia content.
A packet loss repair mechanism at a transport layer of a reliable transmission protocol, such as TCP or SCTP, is essentially a limited retransmission mechanism. Taking TCP as an example, after receiving three consecutive repeated acknowledgement packets, a sender starts a fast retransmission mechanism. If a fast retransmitted packet is also lost, subsequently, retransmission is started according to a set timer. Retransmission intervals are getting larger, and common subsequent retransmission time intervals are 0.5 second, 1 second, 2 seconds, 4 seconds and 8 seconds. If the last retransmission fails, this TCP connection is disconnected.
In a process of implementing the present invention, the inventor finds that the prior art at least has the following problems: The packet loss repair mechanism at the transport layer of TCP and SCTP has a tough characteristic of “repairing until a crash”, that is, if and only if a retransmission repair is successful, subsequent application layer content is sent, and once the retransmission repair fails, the connection is disconnected. For transmission of a real-time streaming media, an existing packet loss repair mechanism of a reliable transmission protocol may cause a screen mess of a picture, a picture jitter or pause, and even a program interrupt, which severely influences picture quality.